The significance is more that the panic-mongers are wrong. Even if California is just following trend, it means that prohibition makes no difference, so from a

The significance is more that the panic-mongers are wrong. Even if California is just following trend, it means that prohibition makes no difference, so from a social policy perspective you have two choices: 1) Some number of people smoke weed, there are no violent gangs involved in its cultivation and sale, harmless college students don't have their lives ruined by a drug arrest and the security-industrial complex gets smaller while its former minions have to go do something that isn't a deadweight loss. 2) Exactly the same number of people smoke weed, there are violent gangs involved in its cultivation and sale, harmless college students have their lives ruined by a drug arrest and the security-industrial complex gets bigger while its minions suck the life out of the productive economy. Which would you choose?